VPP and hierarchical control methods

This chapter introduces a concept and principle of hierarchical control methods for a virtual power plant (VPP) consisting of heterogeneous distributed energy resources (DERs) including energy storage systems. For a VPP, hierarchical control methods enable the VPP to utilize the various capabilities of the DERs by data sharing between higher- and lower-level controls, thereby increasing the flexibility of the VPP in providing electric services in a power system. Therefore, the developments of hierarchical control methods might be the main key to maturing VPP technology in future power systems. The following subchapters introduce and discuss the ancillary services that a VPP may provide, a conceptual hierarchical control structure, functions and applications of the network assets within a VPP, and an example of a hierarchical control method.